Screw-pump.



.application le. april 23, i 7.

To all whom it may concern Be it known that l, Enasrus S. BENNETT, acitizen of the United States, and resident lof New York, N. Y., haveinvented certain new and useful Improvements in Screw- Pumps,of whichthe following is a specication.

My invention is an improvement in rotary screw pumps of the type-inwhich a screw forni of blade is mounted upon a shaft to rotate in acasing and in proximity to a diaphragm supported in said casing, thepurpose being to drive the duid through the casing under high velocity.

The invention is shown in the accompanying drawings, in which,

Figure 1 is a sectional View of a part of a pump casing containing apair of blades made in accordance with my present improvement and adiaphragm of special construction to coperate with the said blades insecuring a proper pumping or forcing action of the water.

Fig. 2' is a detail sectional View of one o the walls of the spokes inthe diaphragm.

Fig. 3 is across sectional' View through the casing illustrating thepropelling blades.

Fig. 3 is a view of the end-or" the blade;

Fig. 4 is a view showing an old form of blade.

In these drawings the casing is indicated at l, within which a shaft 2is located, being mounted in suitable bearings, the shaft having mountedthereon hubs, one o which is indicated at 3 carrying the pumping orpropelling blades 4C which extend from the hub' close to the inner sideof the casing. rllhese blades are arranged in pairs and between thepairs of blades there is a diaphragm composed of a lring 5 held betweensections or" the casing, said diaphragm having radial spokes or arms ofthe form in cross section shown in Fig. 2, that is, these spokes arethickened at their central portion and taper to each edge. The spokesextend from the outer ring 5 to a much longer inner ring 6 arrangedclose about the hubs carrying the blades, these hubs being formed tointerlock as at 7 one with the other. The spokes at their inner ends areof a width, measured along the shaft, equal to the length of the innerring 6 and from this point they taper in width tothe outer ring 5. rlhepropeller blades, instead of being formed as heretofore of screw-shapeshown irl-Fig. 'el are of dat or straight form as indicated in Fig. l,

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and located at an inclination to the axis or" the pump and thisinclination conforms to the incline of the tapered spokes 8 of thediaphragm, as shown in Fig. l.

Referring to Fig. 4f an objection exists to this iorm oi blade in thatthewater will be given a swirling motion to a mate ial degree, which orcourse indicates a lack or" ecienc in the pump. Y

It will be noticed by reference to Fig. that the blades are of largediameter in respect to the diameter of the hub and the tendency is toput the water in circular motion owing to the fact that the angle of theblade at its base or at the hub is much greater in relation to the axisof the blade than the angle at the periphery.

in a 6 blade having a 6 pitch the six inches is gained at the peripherythrough a travel of about nineteen inches, while at the hub say of indiameter the sin inches is gainedA in a little over three inches ofcircular travel.

ln this old style the angular relation of the base of the blade or thatportion adjacent the hub is such to the axis of the pump that the workperormed by this portion of the blade is little more than simply tocause a swirling of the water, this effect diminishing as the peripheryof the bladeV is approached.

ln the improved blade the parts indicated at X in Fig. it are eliminatedand the swirling action of the water resulting from the presence ofthese parts is eliminated in the improved blade shown in Fig. 1, theonly swirling e'ect on the water left inthe improved blade is that dueto the greatly lesscned angle of the periphery, which angular relationcontinues to the hub, the blade being a perfectly straight plate;

rlhe swirling of the water consumes power and is opposed to the forwardmovement ot the Water'through the pump and its elimination increases theeliciency of the pump.

lt will be noticed that the blade of Fig. l rotates in close proximityto the edge of the diaphragm, the spokes of which are shaped to conformto the angular relation of the straight blade and this blade actingclose against the diaphragm outs off the water at the point where thewater is Inoving onward through the diaphragm and where the swirling ofthe water is resisted by the diaphragm and the blade being ot the formshown to eliminate a swirling actien on the Water the result will bethat the Water coming onward through the diaphragn will be impelledonward by the straight flat biade acting thereupon. The suction end ofthe blade is sharpened to reduce resistance.

One advantage of the form of blade disclosed herein is thatit is easierto cast and to finish than the old form and therefore cheapness ofproduction results.

What I claim is:

l. A screw pump comprising a casing, a diaphragm Within the casinghaving openings for the passage of Water therethrough and abladerotating in close proximity to the diaphragm and on each side thereof,said blade being in one plane from end to end and inclined in relationto the axis of the pump, said diaphragm having its opposite sidesreversely inclined in respect to each other and conforming to theinclines of the blades substantially as described.

2. A screw pump comprising a. casing, a

' diaphragm Within the casing having openings for the passageo Watertherethrough gamas-:e

and a blade arranged in one straight plane from end to end and inclinedto the axis of the hub and a diaphragm within the casing composed ofinner and outer rings, the inner ring being longer than the outer ring,spokes connecting the inner and outer ring and tapering in widthoutwardly from the inner hub to the narrow outer ring, said spokes incross section being tapered from the center plane of the diaphragm toeach end thereof, substantially as described.

In testimony whereof, I aEX my signature.

E. s. BENNETT.

